Nefronia en pediatría: dentro del espectro de las infecciones urinarias. Serie clínica y revisión de la literatura / Nephronia in pediatrics: part of the spectrum of upper urinary tract infections. Clinical cases and review of the literature

Nephronia or focal acute nephritis corresponds to a localized inflammatory non-liquefactive kidney infection which may involve parenchyma of one or more renal lobes. It has been suggested that nephronia is part of the spectrum of upper urinary tract infections between acute pyelonephritis and renal abscess. It is associated with a prolonged clinical course, higher levels of inflammatory markers and an increased risk of renal scarring, compared to pyelonephritis. Ultrasound plays a useful role. Nephronia is an under-diagnosed condition, thus, clinical suspicion is important for early diagnosis and appropriate treatment. We present three paediatric cases, and a review of the literature.

La nefronia o nefritis focal aguda es una inflamación renal de etiología bacteriana sin licuefacción que típicamente involucra el parénquima de uno o más lóbulos renales. Dentro del espectro de las infecciones del tracto urinario, se ha planteado que podría ser una entidad intermedia entre la pielonefritis aguda y el absceso renal. Se asocia a un curso clínico más prolongado, mayores marcadores inflamatorios y mayor riesgo de cicatrices renales, al compararla con la pielonefritis. La ecografía renal juega un rol útil en el diagnóstico. Es una entidad subdiagnosticada; por lo que su sospecha es relevante para un diagnóstico oportuno y un tratamiento adecuado. Se presentan tres casos clínicos pediátricos y una revisión del tema.

Nefritis aguda focal: caso clínico / Focal acute nephritis: a case report

Focal acute nephritis (FAN) or acute lobar nephronia is a rare clinical picture characterized by an infection localized in the kidney, with an inflammatory mass without liquefaction. Of variable clinical manifestations, diagnosis is achieved through CT scanning. Histologically, unlike acute pyelonephritis, it does not present a diffuse infíltrate. Objective: Case report of FAN in a pediatric patient. Case Report: Ten year old male complaining of abdominal pain, presents painful percussion in the right lumbar fossa. Urinary analysis and culture were negative, renal sonogram was negative. Abdominal CT sean showed múltiple hypodense renal foci. He responded well to cephotaxim, being discharged in the third day of hospitalization with completion of treatment as outpatient. Differential diagnosis with Acute Pyelonephritis is very important, as it requires controlled and opportune treatment to prevent renal absceses. Diagnosis of this pathology must be pursued despite a normal UA.

La nefritis aguda focal o nefronia lobar aguda constituye un cuadro poco común caracterizado por una infección localizada en el riñon, la que corresponde a una masa inflamatoria sin licuefacción. Posee una clínica variable, siendo la tomograña computada (TAC) la prueba más sensible y específica para el diagnóstico de esta enfermedad. Esta patología se diferencia histológicamente de la pielonefritis aguda por no presentar un infiltrado inflamatorio difuso. Objetivo: presentar un caso de nefronia aguda multifocal en un paciente pediátrico. Caso clínico: Escolar de 10 años que consultó por dolor abdominal, al examen destacaba la presencia de percusión dolorosa en fosa lumbar. Los exámenes de orina y urocultivo fueron negativos. Al ingreso no se detectó cambios renales ecográficamente evidenciables. Se realizó un TAC de abdomen que mostraba múltiples focos renales hipodensos. Respondió favorablemente a terapia antibiótica con cefotaxima siendo dado de alta al tercer día, completando terapia en forma ambulatoria. La diferenciación de este cuadro de otros procesos renales como la pielonefritis aguda (PNA) es muy importante, ya que precisa un tratamiento oportuno y controlado por el riesgo de evolucionar a absceso renal. El diagnóstico de esta patología debe ser buscado a pesar de contar con exámenes de orina negativos.

Clinical Characteristics and Renal Outcomes of Acute Focal Bacterial Nephritis in Children

PURPOSE: This study was performed to elucidate the clinical pictures of acute focal bacterial nephritis(nephronia) in children. METHODS: We reviewed 9 children with nephronia diagnosed by ultrasonography or computed tomography of kidneys from September 1994 to August 2004. RESULTS: The overall male to female ratio was 2:1, and the age distribution ranged from 0.1 to 6 years(mean 2.8+/-2.2). The cardinal symptoms were fever, chills, abdominal pain and dysuria/frequency. The initial leukocyte count was 21,000+/-5,600/uL; ESR, 60+/-23 mm/hr; CRP, 17+/-10 mg/dl. Pyuria was noted in every patient and persisted for 10.5+/-7.8 days after antimicrobial treatment. Abdominal sonography demonstrated focal lesion of ill-defined margin and low echogenicity in 5 of 9 patients(55.6%), while computed tomography revealed nonenhancing low density area in all patients(100%). Three of 9 patients(33.3%) had vesicoureteral reflux, greater than grade III. The initial (99m)Tc-DMSA scan showed one or multiple cortical defects in every patient, and improvements were noted in 2(33.3%) of 6 patients who received follow up scan after 4 months. Intravenous antibiotics was given in every patient under admission. Total febrile period was 11.8+/-6.3 days(pre-admission, 4.0+/-3.0; post-admission, 7.8+/-5.5 days) and the patients needed hospitalization for 17.2+/-8.1 days. CONCLUSION: For the early diagnosis of 'acute focal bacterial nephritis' we should perform renal computed tomography first rather than ultrasonography, when the child has toxic symptoms and severe inflammatory responses in blood and urine.

Focal Bacterial Nephritis (Lobar Nephronia) in a Four-Month Old Boy

Acute lobar nephronia is a focal form of acute bacterial nephritis, affecting one or more of the renal lobules. Nephronia is being diagnosed more frequently in accordance with the advancing imaging techniques of urinary tract. We report a case of acute nephronia in a 4 month old boy who presented persisting urinary tract infection after intial antibiotic treatment. Ultrasonography and computerized tomography showed round wedge-shaped, non-enhancing mass in right kidney. Gallium scan also revealed the lesion in the right kidney. This lesion resolved completely on one month follow up examinations.